White Slime on Beef Shoulder at Cooking

Meat Science and Nutrition

Meat Colour

The post mortem color development of meat varies profoundly from one species to another, with variations in fresh beef being very prominent. Beef shows a range of colour from beginning existence cutting to the end of its shelf life (about three days).

Typical meat color for dissimilar species is shown in Table 3.

Table 3 Typical colour of meat from dissimilar species

Species	Colour
Beef	Bright cerise scarlet
Fish	Pure white to greyness-white or pink to dark red
Horse	Nighttime scarlet
Lamb and mutton	Light carmine to brick red
Pork	Greyish pink
Poultry	Grayness-white to dull red
Veal	Brownish pinkish

Meat colour is significant to consumer acceptance of products. The bright ruddy color of good quality beefiness, sockeye salmon, and young lamb are naturally appealing, whereas the paler colours of veal and other fish species are less highly-seasoned to many (although more than sought later on past some indigenous groups). Dark meats such as horse are more popular in Quebec and European countries. Mutton (sheep over 12 months of age with darker flesh) appeals to an fifty-fifty smaller range of customers.

Factors Affecting Colour

Use of Muscles

Poultry provides a adept opportunity to run across and learn about the differences in meat color. Meat cutters and cooks may oftentimes be asked why different parts of a craven accept and other parts have , or why duck or game birds have more often than not dark meat.

The colour of the meat is determined past how the muscle is used. Upland game birds, such as and grouse, that fly only for short bursts have white breast meat. In contrast, ducks and geese and most other game birds that fly long distances have exclusively nighttime meat. In domestic poultry (chickens and turkeys), there is a deviation between breasts (white meat) and thighs and drumsticks (dark meat).

Note: Craven thighs, even when fully cooked, may take a reddish tinge and blood seepage from the thigh bone. This is normal; still, inexperienced customers may interpret this as a sign of not beingness cooked properly.

Proteins

Meat color is associated with two proteins: (in the muscle) and (in the blood). When animals are no longer alive and air comes in contact with the meat, myoglobin reacts with oxygen in an attempt to reach a state of equilibrium, at which bespeak no further changes occur. As this procedure happens, the meat color goes through three stages and 3 colours that are easy to see, peculiarly on freshly cut beefiness meats.

1. Purplish red (myoglobin): occurs immediately after a is sliced.
2. Cherry red (oxymyoglobin): occurs several minutes after cut and after exposure to oxygen.
3. Dark-brown (metmyoglobin): occurs when the iron in the myoglobin is oxidized, which usually takes well-nigh three days after cutting. (Y'all may run across steaks with this colour in the disbelieve bin at a supermarket. The dark-brown colour doesn't mean there is anything incorrect with the product; in fact, purchasing meat at this stage is a cracking way to stock upward on cheaper steaks for the freezer.)

Oxygen

Oxygen plays two important roles, which touch on the colour in reverse ways. As before long as meat is cut, oxygen reacts with the myoglobin and creates the vivid blood-red color associated with oxymyoglobin. This volition go along to develop until the iron in the myoglobin oxidizes to the point of the stage.

Oxidation can also occur when atomic number 26 in the meat binds with oxygen in the muscle. This can often occur during the processing of round steak from the hip primal and can exist identified past the rainbow-like colours that appear from the reflection of lite off the meat surface. The condition will remain afterward the product is cooked and can often be seen on sliced roast beef used in sandwich making. This condition does non change the quality of the meat; nevertheless, it is generally less attractive to consumers.

Age

The stake muscles of veal carcasses betoken an immature animate being, which has a lower myoglobin count than those of more mature animals. Young cattle are fed primarily milk products to keep their mankind light in colour. However in one case a calf is weaned and begins to swallow grass, its flesh begins to darken. Intact males such every bit convenance bulls accept muscle that contains more myoglobin than females (heifers) or steers (castrated males) at a comparable age.

By and large, beef and lamb have more myoglobin in their muscles than pork, veal, fish, and poultry. Game animals have muscles that are darker than those of domestic animals, in part due to the higher level of physical activity, and therefore they also take higher myoglobin.

Preventing Discolouration

Maintaining the temperature of fresh meat about the freezing point (0°C/32°F) helps maintain the bright red color () of beef meats for much longer and prevents discolouration.

Meat should exist allowed to flower completely (the blossom usually reaches its peak about three or four days after cut) or exist wrapped on a meat tray with a wrapping flick as in supermarket meat displays. If portioned steaks are to be vacuum packed, doing so immediately after cutting (just before the blossom has started) will let the steaks to bloom naturally when removed from the vacuum packaging.

Certain phases of meat processing can as well trigger discolouration. Oxidation browning (metmyoglobin) can develop more speedily than normal if something occurs to restrict the menses of oxygen in one case the bloom has started just has not been allowed to run its full course. The two most common examples are:

• Cut meat surfaces stay in contact likewise long with apartment surfaces such as cut tables, cutting boards, or trays.
• Meat is wrapped in newspaper (which means at that place is no further exposure to air and therefore no oxygen, which speeds up the browning outcome).

The browning result will occur naturally once the meat is exposed to oxygen.

There are two other types of discolouration that unremarkably occur with beefiness and hog meat. Although the cause of both types occurs before death (), the actual change does non show upwards until after expiry (post mortem). The discolouration is a result of chemical reactions in the fauna's body due to stresses, known every bit .

PSS can outcome in ii different types of discolouration: PSE and DFD.

(pale, soft, and exudative) occurs mainly in pigs (and in some cases has been institute to exist genetic). PSE is brought well-nigh past a sudden increase of lactic acid due to the depletion of glycogen earlier slaughter, which in turn causes a rapid pass up in the pH mail slaughter. The visible signs of PSE tin exist detected by the trained center in the pork loin primal, where the flesh appears much paler than normal. The musculus meat is softer and may exist very sloppy and wet to the impact and leaking meat juices, a result of a high proportion of free h2o in the tissues.

Although product with PSE is safe to eat, its shelf life is express and it may become tougher sooner if overcooked. Products with PSE have limited use every bit fresh products but are used to manufacture cooked products such as formed ham and certain sausage varieties with a recommended limit of x% (i.e., 1 office PSE to ix parts of regular meat), due to the high water content.

(dark, house, and dry) occurs mainly in beef carcasses merely sometimes in lamb and turkey. In the meat industry, these carcasses are referred to as . Unlike PSE meat, DFD meat shows little or no drop in the pH later slaughter. Instead, in that location may exist an increase of stress hormones, such as , released into the bloodstream. Consequently, (muscle sugar) is depleted before slaughter due to stresses. This decreases the lactic acid, which in turn affects the pH, causing information technology to not drib fast enough later slaughter. Therefore, the muscle meat, typically in the hip surface area of the carcass, may become very dry and dark.

Even afterwards the carcass is aged and the meat has been processed and displayed, the dark appearance remains and bloom will not occur. In improver, the meat may also feel sticky to the touch, which limits shelf life. DFD meat is generally considered unattractive to the consumer; however, the meat remains edible and is still suitable for use in cooked products and sausage emulsions but should be limited to 10% (one part DFD to nine parts of regular meat).

Listed below are some causes of DFD that should be avoided:

• Transferring animals to strange surroundings (kill establish) and holding them for too long
• Treating animals roughly prior to and during send (e.g., using cattle prods)
• Overcrowding cattle during shipping
• Mixing cattle with other animals they are not used to
• Preventing animals from having sufficient residual at the shambles prior to harvesting
• Dehydrating animals (non giving them enough water) prior to slaughter
• Causing over-excitement, pain, hunger, excessive racket, odor of blood
• Exposing animals to temperature extremes during transportation
• Aircraft stress-susceptible animals, such equally intact males (bulls), during severe weather

Notation: DFD can occur anywhere betwixt 12 and 48 hours prior to an creature's slaughter.

Imperfections and Abnormalities in Meat

Fifty-fifty though meats arriving at their final destination (point of sale) have usually been approved and inspected, the product even so requires further checks prior to sale and eating in case abnormal meat inconsistencies were missed in the inspection process. Some of these are caused by injuries or disease that occurred while the animal was alive, while others are naturally occurring parts of the animal's trunk (glands in detail) that are removed prior to or during the cutting process.

Some examples are given here.

• and : infected or non-infected tumours from old injuries that are imbedded in muscles and sometimes close to basic (Figure ix).

Figure 9. Cyst in beefiness short loin.

• : usually from more recent injuries and also found imbedded in muscles or between muscle seams or on or near bone joints.
• : scar tissue, normally from very erstwhile injuries, with the appearance of white fatty seams or sparse strands tightly bound together, making the musculus tough and unsightly.
• and : lymph nodes are glands in the throat and dorsum of the tongue that give a good indication of the general health of the animal; these are inspected on the brute carcass at the harvesting plant prior to being sold, but internal or intermuscular glands are non examined unless further inspection is recommended past a veterinarian. Consequently, three major glands are removed from beef, pork, and lamb during processing to ensure the public practise not see them. They are the , located in the neck and bract sub-primals below the junction of the fifth cervical vertebra (Figure 10); the , located at 90 degrees to the circular bone on the hip on the exterior of the sirloin tip imbedded in the cod fat pocket (Effigy 11); and the , located in the outside round sub-primal in the hip key between the eye of the round and the exterior round flat under the heel of round, imbedded in a fatty pocket (Figure 12).

Figure 10. Prescapular gland.

Effigy 11. Prefemoral gland.

Figure 12. Popliteal gland.

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Source: https://opentextbc.ca/meatcutting/chapter/meat-colour/

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